Github flow workshops

Slides from Meili

Slides from Denise

If you don't have a GitHub account yet, sign up

If you don't have git on your machine, install and configure it

Come over to me to add you as a collaborator of this repository.

Now clone the repository to your machine. Go to your GitHub account, open the repository, click on the clone button and then click the copy to clipboard icon.

Open a terminal and run the following git command:

git clone <url you just copied>

where "url you just copied" (without the < > signs) is the url to this repository. See the previous steps to obtain the url.

Change to the repository directory on your computer (if you are not already there):

cd github-workshop

Now create a branch using the git checkout command:

git checkout -b <add-your-new-branch-name>

On your branch (local copy of the repository) you will edit the file commit-messages.md in this repository and add some tips on how to write good commit messages. Give your branch a meaningful name, including your name so that it is not the same as the branch of everyone else in the workshop.

For example:

git checkout -b add-george-tips

Now open commit-messages.md file in a text editor, and add your tips for writing good commit messages. Save the changed markdown file.

If you go to the project directory and execute the command git status, you'll see there are changes.

Add those changes to the branch you just created using the git add command:

git add commit-messages.md

Hit git status again to see how the changes are still there but now they are staged for commit (it's a necessary preparation)

Now commit those changes with a nice commit message using the git commit command:

git commit -m "Add HERE your commit message"

replacing the text in "" with your commit message.

Up until now, you have not submitted anything to GitHub!

Push your changes using the command git push:

git push origin <add-your-branch-name>

replacing <add-your-branch-name> with the name of the branch you created earlier.

Now go to your repository on GitHub, you'll see a Compare & pull request button. Click on that button.

Before sumitting the Pull Request, make sure to change the base repository from mei-li/github-workshop to the current fork of the repo denisesenguel/github-workshop. Afterwards it should be master at the left and your branch at the right. It should look something like this

You may change the title of the Pull request if you want to. It should be short but informative about all the changes you did. Now submit the pull request.

Now exchange reviewes with a person sitting near you. In GitHub you can assign them as a reviewer in your Pull Request or tell/send them your Pull request number.

Github offers 2 ways of reviewing, either with single comments or with start review that let you add multiple comments that will be visible when selecting the submit review. This way they will show all together. Use the single comments

Add a review and ask the author to make some change. A review should be respectful and explain the reason that the change is needed, giving context.

Address the comments of the review or reply to them explaining your reasoning. If see that the suggested changes make sense, make the changes locally and save. Then add, commit and push the updates to GitHub as you did with the initial changes.

Use a meaningful commit message when addressing the comments eg. Improve wording instead of addressing comments

Congrats! You just completed the standard clone -> edit -> PR_ workflow that helps you collaborate and share knowledge with your team!

If you realize that you want to undo some changes you've made, you have several options and it depends on what you have done before. Rewritting history in git is possible. One should be careful not to do that, in general because changes might get lost and in particular on any branch that is already shared with somebody else. To be on the safe side do history rewrites before pushing the commits or even better in an additional branch!

• If you have not added (we call it "staged") or commited a change yet git checkout <filename> removes all of the local changes on the file. Be careful with this one, you might easily lose relevant work
• If you have already added but not yet commited a change git reset HEAD <filename>

For changes that have already been commited:

• git commit --amend -m "your new commit message" lets you add some changes to your previous commit (use on private branches only)
• git revert <commitID> lets you undo a specific commit as an additional commit. This is a very safe option also if you shared a branch already
• git reset --soft <commitID> there is also a --hard flag but don't use it unless you know exactly what you are doing!

Get the ugly-history branch and start a new branch from it

git checkout <ugly-history>
git checkout -b <your_new_branch>

Use git log to look at the commit history (last 10 commits)

git log -10

Revert the commit where commit-message.md is added by running

git revert --no-edit <commit hash> 

and again check your commit history. The commit ID can be obtained from the commit history.

Now undo the last 5 commits and split them into two, one adding the hello.py file and one the goodbye.py Use

git reset --soft HEAD~5

Then add and commit as described.

Imagine that you forgot to add some comment. Add a random comment to hello.pyor goodbye.py and amend the last commit.

Push your new branch and make a Pull request. Ask for your reviewer to check the commits.

As the name suggests .gitignore is a list of files to be ignored by git. That means that changes in these files will not be tracked and thus also not end up on GitHub or any other hosting service. (example: sensitive data)

Add a new empty file of any type to your repository. Open the hidden file .gitignore via your Terminal in a text editor. Add the new file you just created and another previously existing file in your repository to the file list. Add and commit your changes and watch what happens to understand .gitignore better.

Team up with your collaborators. Merge one of your reviewed pull requests and then see what happens with your open pull requests!

If a command like add, commit or reset applies to all of your changed files (not just one) use for example git add . or git add * to not run the command on every single file separately.

To make your git log look more compact like this:

16fed12 [4 minutes ago] (Meili Triantafyllidi) improve commit message tip
5a964a3 [13 minutes ago] (Meili Triantafyllidi) add slides and start part II
13ddeff [14 minutes ago] (Meili Triantafyllidi) add assets
707334e [4 hours ago] (Meili Triantafyllidi) add github workflow part I

you can edit your .gitconfig file which is in you home directory and add this in the format section. Like this:

[format]
  pretty = %C(magenta reverse)%h%Creset %Cgreen[%cr]%Creset (%an) %s

More to be added.

Gitlab workshop: Gitlab workflow